In fact, this announcement is a crucial step if Google really wants to replace the traditional desktop productivity applications with cloud services, and if he wants to eventually make it right.
Recall that Google has made already several attempts to introduce the offline functionality of its cloud services. Offline functionality was implemented, however, using several independent solutions. Google Gears plug-in (with not quite intuitive controls), was responsible for working offline with documents. It has already been discontinued. Offline Gmail and Google Calendar were implemented by separate applications running in Chrome browser. Well, from user’s point of view, these solutions are far from perfect. Why should we decide before we go to e-mail if we want to use its online (browser) or offline (app) version? Why should we ever care that before being able to work offline we have to install several apps, that are different for different services?
Offline synchronization should be seamless and automatic, irrespective of type of information, and without user intervention or even knowledge. Users should be able to use a single user interface regardless of whether they are working online or offline and should not be interrupted from their work every time the connection drops. These things are clear and obvious.
So let's keep our fingers crossed to Google, that this time, the online functionality is implemented properly. At last.